package com.test.netty.demo.util;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * 全局ApplicationContext
 * @author yousj
 *
 */
@Component
public class SpringApplicationContext implements ApplicationContextAware, DisposableBean {

	private static ApplicationContext applicationContext = null;


	/**
	 * 实现ApplicationContextAware接口, 注入Context到静态变量中.
	 */
	public void setApplicationContext(ApplicationContext applicationContext) {

		if (SpringApplicationContext.applicationContext != null) {
		}

		SpringApplicationContext.applicationContext = applicationContext;
	}

	/**
	 * 实现DisposableBean接口,在Context关闭时清理静态变量.
	 */
	public void destroy() throws Exception {
		SpringApplicationContext.clear();
	}

	/**
	 * 取得存储在静态变量中的ApplicationContext.
	 */
	public static ApplicationContext getApplicationContext() {
		assertContextInjected();
		return applicationContext;
	}

	/**
	 * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String name) {
		assertContextInjected();
		return (T) applicationContext.getBean(name);
	}

	/**
	 * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	public static <T> T getBean(Class<T> requiredType) {
		assertContextInjected();
		return applicationContext.getBean(requiredType);
	}

	/**
	 * 清除SpringContextHolder中的ApplicationContext为Null.
	 */
	public static void clear() {
		applicationContext = null;
	}

	/**
	 * 检查ApplicationContext不为空.
	 */
	private static void assertContextInjected() {
		if (applicationContext == null) {
			throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringApplicationContext");
		}
	}
	/**
	 * 判断是否进行了系统ApplicationContext的初始化
	 * @return
	 */
	public static boolean isInitApplicationContext(){
		return applicationContext != null;
	}
}
